Is a year a leap year in the Gregorian, Julian, Hebrew, Islamic (tabular) or Per...

{ "method": "GET", "queryParams": { "calendar": "gregorian", "year": 1900 }, "type": "http" }

{ "example": { "asOf": "2026-10-11T08:54:33.894Z", "calendar": "gregorian", "daysInYear": 365, "degraded": false, "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.", "leapCycle": "400 years: 97 leap years", "leapYear": false, "nextLeapYear": 1904, "notChecked": [ "the Chinese calendar (leap months depend on astronomy and are not covered here)", "historical errors: the Julian calendar was misapplied in Rome until about 8 CE", "…2 more" ], "previousLeapYear": 1896, "reasons": [ "Divisible by 4, except century years, which must be divisible by 400 (1900 is not leap, 2000 is).", "A common year has no added period." ], "rule": "Divisible by 4, except century years, which must be divisible by 400 (1900 is not leap, 2000 is).", "source": "Published leap rules (Reingold and Dershowitz; Persian by Meeus equinox), computed locally", "summary": "1900 is not a leap year in the gregorian calendar (365 days).", "verdict": "COMMON_YEAR", "year": 1900 }, "type": "json" }